MRI: Acquisition of a Dual Size Exclusion Chromatography-Asymmetric Flow Field Flow Fractionation (SEC-AFFFF) Instrument, James McGrath, Kevin Edgar, Richey Davis, Richard Turner and Judy Riffle, Depts of Chemistry, Wood Science and Forest Products, Chemical Engineering and the Macromolecules and Interfaces Institute, VA Tech, Blacksburg, VA A centralized, multi-user SEC-AFFFF facility is requested to characterize absolute molecular weights and sizes of a diverse array of homo- and copolymers and macromolecular colloidal assemblies. The sizes of macromolecules in solution are intrinsically related to their molecular parameters such as the type, amount and locations of ionic groups, copolymer microstructure, hydrophobic/hydrophilic nature, architectures, phase structures, tacticities, and intra- and inter-molecular interactions. In turn, the sizes control functions such as mechanical, thermal, and transport properties as well as the propensity for cooperative complexation to assemble into supramolecular constructs. Polymer research at VA Tech emphasizes the synthetic chemistry of macromolecules, particularly on charged and multi-phase structures, high and low molecular weight materials with extensive hydrogen bonding, and on molecules with varied architectures, and such systems present great challenges for accurate characterization of their sizes. Moreover, our growing emphasis on natural polymers including functionally-modified polysaccharides and highly-charged nucleic acids present unique difficulties in measurements and interpretation of molecular weight analyses. An analytical SEC-AFFFF facility with multiple integrated detectors to measure on-line refractive indices, UV absorbance, dilute solution viscosities and light scattering, to handle aqueous and organic solvents, and to operate over a wide range of molecular weights is requested to characterize these polymers and self-assembled structures. The SEC-AFFFF facility will allow measurement of absolute molecular weights, intrinsic viscosities, virial coefficients, degrees of branching, aggregation characteristics, complex sizes, chemical stability, and biodegradation for a vast collection of chemical compositions. SEC and AFFFF methods will be integrated into undergraduate and graduate coursework, academic year research and summer undergraduate programs. Our goal is to impact society through research in alternative energy solutions, water purification, gas separations, medical diagnostics and new molecular carriers for therapeutics.
NON-TECHNICAL SUMMARY: MRI: Acquisition of a Dual Size Exclusion Chromatography-Asymmetric Flow Field Flow Fractionation (SEC-AFFFF) Instrument, James McGrath, Kevin Edgar, Richey Davis, Richard Turner and Judy Riffle, Depts of Chemistry, Wood Science and Forest Products, Chemical Engineering and the Macromolecules and Interfaces Institute, VA Tech, Blacksburg, VA Molecular weights and sizes of macromolecules and nanoscale polymer aggregates represent one of the most critical parameters that define their properties and potential applications. The sizes control functions such as mechanical, thermal, and transport properties as well as the capacity to assemble into nanomaterial complexes. Polymer research at VA Tech emphasizes the design, synthesis and properties of multiphase and charged polymers with a wide range of molecular weights that present great challenges for accurate characterization of their sizes. The functionality and phase structures of these polymers lead to materials for alternative energy solutions, water purification, gas separations, medical diagnostics and new molecular carriers for therapeutics. This proposal requests a dual SEC-AFFFF for a centralized, multi-user facility. SEC is the premier characterization tool for determining the molecular weights of both synthetic and natural polymers. AFFFF is a relatively new analytical method that particularly enables separations of very high molecular weight polymers, charged polymers, micelles, polymer-drug complexes and nanoparticles. The facility will be integrated into coursework and research at both the undergraduate and graduate levels, and will also be available to regional institutions outside of VA Tech.
